Process of vulcanizing caoutchouc and product obtained thereby



Patented Apr. 6, 1926.

DEXTER N. SHAW, 0F PHILADELPHIA. PENNSYLVANIA, ASSIGNQE 1 0 THE GOULD YEAR TIRE 8c RUBBER COMTPANY, 0F AKRON, OHIO, A CORPORATIGH 0F OHI IG.

PROCESS OF VULCANIZING CAOUTCHOUC AND PRODUCT OBTAINED THEREBY.

No Drawing.

1c caoutchouc and caoutchouc compounds, and

it has, for its primary obj eet, the provision of accelerators of high curing power which will insure a product of high tensile stren 'th and good aging qualities. More particu arly, it related to the use of isomers of nitrosocarbazole and their derivatives.

Carbazole is a by-product of the coal-tar industry and, though it has some use in the manufacture of dye-studs, the supply for eX- J coeds the demand. By far the greater portion is used as a fuel, crude solvent, or remains in the tar only to be used for paving purposes. Though the supply and demand have so adjusted themselves that the purified material is available only at a moderately high price, it new outlet will not only encourage competition for its recovery and thus eliminate this wasteful use of a valuable intermediate, but also reduce its unitcost.

I have found, that by treating edrbazole with a solution of sodium nitrite and acid, a

bright yellow flaky material is isolated,

which has a melting point at about 82 C. This substance is probably formed by the following reaction:

Though, in this form it is not suitable as rapid accelerator, whenltreated with hydroohloric'ecid, in the presence of acetic Application filed ll'ovem'ber 18, 1924. Serial Ito. 750,672.

acid, it undergoes a rearrangement which may be represented in the following manner:

mm: o uron 3-nltrosocurbuzole n-nitro socerbazole When S-nitrosocarbozole is milled into a rubber mix, it shows some scorching effects, and, though it gives excellent results whet) used in the usual manner, I have found that its capacity to effect vulcanization at a low temperature is such that it may also beused in air curiihg.

1 have also found that the isomer having the nitroso group in position 3 can be prepared directly without first separating the normal or 1 nitroso derivative. By treatin cerbazole, dissolved in acetic acid and et er, with a metallic nitrite in the presence of water, the n-nitroso'carbezole is formed; but, with a suficiently high concentration of acetic acid, it is not precipitated. On further treating this material with hydrochloric acid and allowing it tostend for some time, a. green precipiteteof the 3-ilitrosocerbazole is obtained, which may be completely pre eipitated by diluting the mixture with water."

As is commonly known, most inorganic acids are detrimental to vulcanization, so I have found that this material must be Washed several times with water to remove any adsorbed acid.

The reaction for the preparation of 3- nitrosocarbazole is almost quantitative and I have had no ditfieulty in obtaining a 95% yield. The compound which results from the above procedure has no definite melting point, but decomposes between 150 and 160 3 1' here incorporated this material in foitowing; ratio 01 ingredirubber, t; parts activator, pert accelerator, end have satisfactory cure in (it) minutes g the mix temperature corto 4K) pounds steam pressure. prod ct has an eicngation of 780%, at the breaking iced 111.5 kgs/cmF. Zinc oxide or are ts he preferred as activators, thong: edits of these metuis can be used sncccsstuiiy. 1

it shouid he understa ed that I am neither tiinited hy the examples nor the theories set tort-h by we of explanation and, though I have sipecitireiiy described an accelerator that may he used in promoting the vulcanization of ruhhcr, either with or Without the aid of heat. it obvious, that minor changes may he made in the appiication without departing from the scope thereof; I desire, theret'ore, that only such limitations shall be imposed as are required by prior art endthe iended cieim's. rt hut 1 claim is:

method of vulcunizing cuoutchouc stock hating the ents; 100 Darts parts su it ur, 1 Ubilltil'lfiti i 1 ft the vulcanizing agent, imrorporuting a nitrosoctnibazoie therein, mixing an activator therewith er ppiying heat.

ses admixing caoutchouc with a .ui agent, incorporating a mtrosot; comprises-s admixing caoutchouc with it thod of vulcanizing caoutchouc eeeese carbazoie therein, and mixing an activator therewith.

3. A inethed of accelerating the vulcanization of cecutchouc that comprises vulczin izing the Same in the presence of a, nitrmocerhuzoie derivative.

4. The method of accelerating the ruicani zation of ceoutchouc that comm-E505 vuiczanizing the same in the pit-SCUM) of a rurhw Zoie derivative.

A method of \Hh'ttiliZillQ czuuttchouc that comprises admixing cuoutt-houc with u ruh-anizing' agent, inctn'poruting 3-nitrosocarhazole therein, mixing an activator time with and appiying heat.

(5. A method of ruh-unizing caoutchouc that comprises admixing; caoutchouc with 2t vulcanizing'agent, incorporating: :hliittUSO- curbazoie therein and mixing an zu-tivutor therewith.

'2'. A product formed hy the reaction 05 cuoutchouc, a, vuicztnizing agent, an activetor and nitrosocurbazoie.

8. A product formed by the reaction of czwutchouc, a vulcunizing agent, an activator and a derivative of nitrosocarhezoie.

5). A product formed by the reaction of mioutchouc, a vulcanizing agent, an eetivm tor, and 3-11itrosocerhnzoie.

. In witness whereof, i have signed my name.

hereunto DEXTER N. SHAVE, 

